Stock futures rise as Putin reportedly ready for Ukraine talks

U.S. stock-index futures signaled a higher Wall Street open on Wednesday, with investors welcoming reports that Russian President Vladimir Putin was willing to discuss the crisis in Ukraine with regional leaders.

"We had a tone change that is corresponding with news that Putin is willing to discuss his way out of the crisis. If in fact the biggest hang on this market is geopolitical, then there's a glimmer of hope here," said Art Hogan, chief market strategist at Wunderlich Securities.

Stock futures turned from mixed to higher after Bloomberg cited Interfax in reporting Putin planned to discuss Ukraine on Thursday with regional leaders attending a meeting in Moscow.

And, futures largely retained their gains after the government reported productivity falling 1.7 percent in the first quarter, versus estimates calling for a 1.1 percent drop.

Futures had been mixed ahead of Federal Reserve Chair Janet Yellen's congressional testimony later in the day.

The Fed chair will speak at 10 a.m. ET. While she is expected to maintain her dovish stance, investors will be watching out for any hints as to the timing of future interest rate hikes.

"Yellen's prepared remarks will likely focus on the Federal Open Market Committee (FOMC)'s broader views on the economic outlook, but the Q&A will be equally as important," said Jim Reid of Deutsche Bank in a morning research note.

"It is possible she may be asked by Senate Committee members for more clarity on the Fed's exit strategy and/or its view on the terminal funds rate—a heavily debated topic in the financial markets at the moment," he added.

Tim Harris, CEO of Harris Capital, says the earnings momentum is starting to turn positive in the U.S. and the rest of the year should accelerating growth for equities.

Earlier in the day, Fiat-Chrysler shares dived 7 percent on investor disappointment with the carmaker's ambitious plan to boost sales by 60 percent by 2018 by betting on premium brands such as Jeep and Alfa Romeo.

In additions, French engineering group Alstom reported results, but provided no update on rival bids from General Electric and Siemens for its power and grid business.

In other corporate news, Chinese e-commerce giant Alibaba filed a much-anticipated initial public offering (IPO) prospectus late Tuesday in the U.S.

Recent estimates put Alibaba's value between $150 billion to $200 billion. That suggests the IPO could raise up to $15 billion, making it one of the biggest tech IPOs since Facebook listed its shares in 2012.